%%
%% The LaTeX Companion, 3ed
%%
%% Example A-3-21 on page II-670 in "Manipulating boxed material".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See
https://www.latex-project.org/lppl.txt for details.
%%
\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{111.0pt}
%StartShownPreambleCommands
\usepackage{calc}
\newsavebox{\fcolbox} \newlength{\fcolwidth}
\newenvironment{fcolumn}[1][\linewidth]
{\setlength{\fcolwidth}{#1-2\fboxsep-2\fboxrule}%
\begin{lrbox}{\fcolbox}\begin{minipage}{\fcolwidth}}
{\end{minipage}\end{lrbox}\noindent\fbox{\usebox{\fcolbox}}}
%StopShownPreambleCommands
\begin{document}
\begin{fcolumn} In this environment verbatim text like
\verb=\fcolbox= can be used. \end{fcolumn}
\end{document}
